ROME, May 10 (Reuters) - Italian industrial output was much weaker than expected in March, falling 0.5% from the month before after a flat reading in February and extending the pain for the country's struggling manufacturing sector, data showed Friday.

A Reuters survey of 16 analysts had pointed to a 0.3% monthly gain in March.

February's data was revised down from an originally reported +0.1%.

On a work-day adjusted year-on-year basis, industrial production in the euro zone's third largest economy was down 3.5% in March, national statistics bureau ISTAT said, a 14th consecutive decline.

Over the first quarter, output was down 1.3% compared with the fourth quarter of 2023.

March saw declines in output of consumer items, intermediate goods, and especially investment good, which dropped 3.8% from the month before.

These falls were partly offset by a 1.7% monthly rise in output of energy products.

Italian gross domestic product rose 0.3% in the first quarter from the previous three months, preliminary data showed last week, following marginal 0.1% growth in the fourth quarter of 2023.

Most analysts expect similar weak growth in the coming quarters, yielding full year expansion of between 0.7% and 1%, broadly in line with last year's 0.9% rate.

(Reporting by Valentina Consiglio and Gavin Jones, graphic by Stefano Bernabei)